Process-based modeling analyses of Sabina przewalskii growth response to climate factors around the northeastern Qaidam Basin

Sabina przewalskii is the longest living endemic tree species in the northeastern Tibetan Plateau, and has been widely employed in tree ring based climate research in China. However, most dendroclimatic reconstructions have been primarily based on empirical relationships between tree growth and climate factors identified by statistical assessment. To date, the physiological relationships between tree growth and their limiting climate factors have not been properly assessed. Here, we simulated the physiological response of Sabina przewalskii tree growth to major limiting climate factors based on the Vaganov-Shashkin (VS) model. The VS modeled results validated the relationships between tree ring and climate factors constructed by statistical models, both approaches suggesting that precipitation during the early growing season, especially in May and June, has significant effect on tree growth, while temperature mainly affects tree growth by warming-induced drought and by extending the growing season. Under current and projected climate scenarios, our modeling results predict an increase in radial growth of Sabina przewalskii around the Qaidam Basin, with the potential outcome that regional forests will increase their capacity to sequester carbon.